Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

CTO Quiz 2 > CTO_Muscle_Quiz2 > Flashcards

CTO_Muscle_Quiz2 Flashcards

(68 cards)

Start Studying
1
Q

Three types of mucsle

A
  1. skeletal; 2. cardiac; 3. smooth
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Skeletal muscle - features overview

A

fast contracting, powerful, voluntary control, discontinuous activity; e.g. tonuge, upper esophagus, diaphragm

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Cardiac muscle - features overview

A

striated, fast contracting (rhythmic), powerful, involuntary, continuous activity, mutlinucleated syncytium (peripheral nuclei)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Smooth muscle - features overview

A

slow contracting, weak, involuntary control, discontinuous activity; e.g. blood vessels, respiratory passages, GI & GU tract

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Fx of muscle

A

produce body movements, stabilize body positions, regulate organ volume (wall of GI tract & smooth muscle sphincters), flow of substances within body (blood, lymph, urine, air, food, fluids, ova, spermatazoa), produce heat (involuntary contractions of skeletal muscle, i.e. shivering)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Properties of muscle tissue

A
  1. excitability; 2. conductivity; 3. contactility; 4.extensibility; 5. elasticity
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Response of skeletal muscle to increased demand

A

hypertrophy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Skeletal muscle support

A

CT: epimysium, perimysium, endomysium

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Skeletal muscle fiber length

A

10-100 micrometer diameter, > 100 cm in length

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Sarcomere

A

functional unit of contraction (z disc to z disc) => striped apperance

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Epimysium

A

layer of connective tissue covering the entire muscle (dense irregular CT); continuous with fascia and other CT wrappings of the muscle; protects muscles from friction against other muscles and bones

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Perimysium

A

sheath of connective tissue that groups muscle fibers into fascicles

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Endomysium

A

layer of loose connective tissue covering each individual muscle fiber (includes reticular fibers); contains capillaries, nerves, and lymphatics; overlies sarcolemma.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

List the hierarchical organization of muscle

A

Muscle->Fascicle->Fiber->Myofibrils->Myofilaments [thick & thin]

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Sarcolemma

A

cell membrane of skeletal, cardiac, and smooth muscle; consists of a true cell membrane + external lamina (basement membrane)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Muscle in cross section

A

polygonal; peripheral nuclei, blood vessels within CT

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Skeletal muscle - development

A

100 myoblasts fuse to makean immature multinucleate muscle fiber (terminally differentiated); some myoblasts become satellite cells that retain ability to regenerate new cells. Mature muscle cells do not divide.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

How do skeletal muscles grow?

A

hypertrophy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

I band

A

Isotropic: light band in polarized light

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

A band

A

Anisotropic: dark band blocking polarized light; contains heavy myosin filaments

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Z disc

A

located in the middle of I bands; define borders between contractile units such that A bands are in the middle of the contractile unit; attachment point for adjacent actin filaments in sarcomere

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

M line

A

attachment of adjacent myosin molecules in sarcomere

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Protein types present in myofibrils

A
  1. Contractile proteins (myosin II & actine); 2. Regulatory proteins (turn contraction on/off); 3. Structural proteins (for proper alignment, elasticity, extensibility)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Regulatory proteins of skeletal muscle myofibrils

A

troponin complex, tropomyosin, myosin light chain kinase (MLCK)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Structural proteins of skeletal muscle myofibrils
titin, myomesin, nebulin, alpha-actinin, dystrophin, and intermediate filaments (3 types)
26
Intermediate filaments of skeletal muscle myofibrils
desmin, vimentin, synemin - located between contractile proteins, important at Z disc
27
Tropomyosin
long, rod shaped protein paralleling actin double helix; stabilizes actin filament and covers myosin binding site during muscle relaxation
28
Troponin complex
consists of 3 proteins: troponin T - binds tropomyosin; troponin C - binds Ca2+; troponin I - binds actin and inhibits myosin binding
29
Myosin II
form of myosin in skeletal muscle consisting of a coiled coil of 2 alpha helices; head region contains 2 heavy chains with globular head on "hinge region", 2 lights chains, 2 regulatory light chains; self-assemble; polarized
30
Actin binding protein
binds to actin to create cross-bridges necessary for contraction
31
Mechanoenzyme
an ATPase that uses energy from ATP hydrolysis to detach cross bridges
32
Z line
anchor where + ends of actin meet
33
I band - cross section
actin + actin-associated proteins
34
H band - cross section
myosin only - no actin overlap; subset of the A band
35
A band overlap - cross section
myosin and myosin with actin (interdigiating filaments)
36
M line - cross section
where myosin tails meet ("bare area") and myosin-binding structural proteins
37
Muscle contraction: description of sarcomere
Z disc moves toward A band => I band and H band decrease in width due to increased actin/myosin cross bridges (A band width is constant)
38
What initiates muscle contraction?
entry of Ca2+ into sarcoplasm -> binds to troponin C -> configurational change to expose binding sites for myosin to bind with actin
39
Power stroke
Binding of myosin to myosin-binding site on actin -> release of ADP from head of myosin -> conformational change pulling actin toward -end of actin filament => adjacent Z discs move closer together = shortening of sarcomere (NO ENERGY EXPENDED)
40
Rigor mortis
condition (3-4 hrs post-mortem) where ATP has been used up but Ca2+ leaks from sarcoplasmic reticulum; lasts until muscle proteins break down (2-3 days)
41
How does myosin release its grip on actin?
by binding ATP, but does not require hydrolysis
42
How does myosin recock its head to prepare for the next contraction?
ATP hydrolysis where phosphate remains attached until myosin binds actin again; note: to change muscle length significantly this cycle must be repeated multiple times
43
How many myosin molecules pull on a single actin filament?
hundreds
44
T-tubules
invaginations of sarcolemma that surround myofibrils to form triads with 2 cisternae of sarcoplasmic reticulum that convey electrical signals from membrane into the cell => rapid depolarization
45
How are contractions initiated?
nerve activity -> rapid depolarization of membrane + t-tubule -> conformational change in voltage-gated Ca2+ channels -> opens Ca2+ channels -> opens Ca2+ channels on sarcoplasmic reticulum -> release of stored Ca2+
46
Neuromuscular junction
synapse of motor neuron on muscle fiber; one per skeletal muscle fiber
47
Motor unit
group of muscle fibers innervated by one nerve fiber with multiple neuromuscular junctions that contract synchronously
48
Acetylcholine
neurotransmitter (delivered in vesicles at motor end plate) used to excite skeletal muscle; ~30x10^6 Ach receptors in a motor end plate
49
Cardiac muscle
striated with centrally located nuclei, individual muscle cells are short & quadrangular, separated by intercalated discs; branching cells; similar arrangement of thick & thin filaments as seen in skeletal muscles
50
intercalated discs
connections between adjacent cardiac muscle cells with adhering junctions and gap junctions; transvere portions: fascia adherens (siimlar to broad desmosomes); vertical portions: desmosomes and gap junctions;
51
Regulation of cardiac muscle
autonomic nervous system and autorhythmicity (periodic depolarizations)
52
T-tubules in cardiac muscle
exist at Z lines and in apposition to only 1 cisterna => dyads
53
How does cardiac muscle grow?
hypertrophy in response to demand (no mitosis or regeneration)
54
Why is cardiac muscle rich in mitochondria (located between sarcomeres)
heart muscle cannot run out of energy
55
Smooth muscle
single fusiform cells with central nucleus, "dense plaques" contain contractile proteins and intermediate filaments; surrounded by network of reticular fibers that act as scaffolding; gap junctions; no striations or indication of contractile system or communication
56
How does smooth muscle grow?
hyperplasia and hypertrophy in response to demand and proliferation via mitosis
57
invagination of sarcoplasmic reticulum and vesicle-like caveoli
location of Ca2+ in smooth muscle as opposed to t-tubule system (less sarcoplasmic reticulum compared to other muscle types)
58
Corkscrew contraction
non-linear contraction of acint & myosin attached to dense bodies along PM of smooth muscle
59
Dense bodies
contain alpha-actinin, sites of attachment of connecting proteins, contractile fibers, and supporting fibers with each other and basement membrane
60
Initiation of contraction - smooth muscle
intracellular Ca2+ stores from SR = trigger for contraction; increase in extracellular Ca2+ -> binds to calmodulin -> activates MLCK -> phosphorylation of myosin light chains -> conformational change of myosin -> active myosin binds actin (cross bridge cycle);
61
End of contraction - smooth muscle
phosphatases inactive myosin
62
Regulation of smooth muscle contraction
involuntary, but modulated by autonomic nervous system and hormones for contraction of specific smooth muscles
63
Requirements/important elements for smooth muscle contraction
Ca2+, calmodulin, myosin light chain kinase (MLCK)
64
Contractile mechanism - smooth muscle
actin and myosin (different ratio), intermediate filaments required
65
Axon terminals associated with smooth muscle
axons contain vesicle-containing varicosities at various points along axon terminal and influence surroounding smooth muscle cells
66
Visceral type smooth muscle units
exist in sheets with extensive gap junctions but sparse innervation -> coordinate contraction waves (peristalsis); e.g. gut, uterus
67
Multiunit type smooth muscle units
heavily innervated smooth muscle where cells behave more independently -> precise and rapid contraction; e.g. smooth muscle of eye, arrector pili
68
Myoepithelial cells
located near glands, derived from epithelium, reside inside basement membrane -> assist with movement of secretions; contain actin and myosin => contractile

CTO Quiz 2 (1 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions